Make your own Biodiesel Part 1
There are at least three ways to run a diesel engine on biofuel using veggie oils, animal fats or both. All 3 are used with both fresh and secondhand oils.
1. Use the oil just as it is-- generally called SVO fuel (straight vegetable oil);
2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or blend it with a solvent, or with gas;
3. Convert it to biodiesel.
The first two methods sound most convenient, but, as so often in life, it's not rather that simple.
1. Mixing it
Grease is a lot more thick (thicker) than either petro-diesel or biodiesel. The purpose of mixing it or blending it with other fuels is to reduce the viscosity to make it thinner so that it flows more freely through the fuel system into the combustion chamber.
If you're blending veg-oil with petroleum diesel or kerosene (exact same as # 1 diesel) you're still utilizing fossilfuel-- cleaner than most, but still unclean enough, lots of would say. Still, for every gallon of
grease you utilize, that's one gallon of fossil-fuel conserved, and that much less climate-changing carbon in the atmosphere.
People utilize numerous mixes, ranging from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some people simply it that way, launch and go, without pre-heating it (that makes veg-oil much thinner), and even use pure grease without pre-heating it, which would make it much thinner.
You may get away with it with an older Mercedes 5-cylinder IDI diesel, which is a very hard and tolerant motor-- it won't like it however you most likely won't eliminate it. Otherwise, it's not sensible.
To do it properly you'll require what totals up to an SVO system with fuel pre-heating anyway, preferably using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the blends.
Blends with numerous solvents and/or with unleaded gas are "speculative at finest", little or nothing is understood about their effects on the combustion characteristics of the fuel or their long-lasting impacts on the engine.
Higher viscosity is not the only problem with utilizing vegetable oil as fuel. Veg-oil has different chemical homes and combustion characteristics from the petroleum diesel fuel for which diesel engines and their fuel systems are created.
Diesel engines are state-of-the-art machines with extremely precise fuel requirements, particularly the more modern-day, cleaner-burning diesels (see The TDI-SVO debate).
They are difficult but they'll just take a lot abuse. There's no assurance of it, however using a mix of approximately 20% veg-oil of excellent quality is stated to be safe enough for older diesels, especially in summer season.
Otherwise using veg-oil fuel requires either a professional SVO solution or biodiesel. Mixes and blends are generally a poor compromise. But mixes do have a benefit in winter.
As with biodiesel, some kerosene or winterised petro-diesel fuel mixed with straight grease lowers the temperature at which it begins to gel. (See Using biodiesel in winter season) More about fuel blending and blends.